Electric hoist



P. WHITCOMB ELECTR Aug. 20, 1940.

IC HOIST Filed Oct. 6, 1937' 4 snags-sheet 1 Aug. 20, 1940. P. WHITCOMB2,211,873

ELECTRIC HOIST Filed Oct. 6, 1937 4 Shuts-Sheet 2 I INVENTOR. 9

ATTORNEYJ P. WHITCOMB ELECTRIC HOIST Aug. 20, 1940.

Filed Oct. 6, 1937 4 Sheets-Sheet 3 INVENTOR. Fresh Whif'comb MITORNEYS,

Aug. 20, 1940. P. WHlfCOMB 7 2,211,873

ELECTRIC HOIS'I Filed 001.. 6, 1937 4 Sheets-Sheet 4 INVENTOR. fiehmwhifcomb RNEYS Patented Aug. 20, 1940 UNITED 'STATES PATENT OFFICEEIEOTRIO HOIST Application October 6, 1937, Serial No. 167,484

1 Claim.

This invention relates to improvements in small electric hoists.

An object of the invention is to provide a compact, simple and ruggedhoist structure which 8 in proportion to the loads it is capable oflifting is remarkably light in weight and small in size.

A further object of the invention is to provide an electric motor hoistadapted for hook suspension, which is of such character as to provide10, maximum strength and good balance about a central vertical axis withlow cost and simplicity of construction.

Further and more specific objects of the invention as will appear beloware successfully secured 15 thereby.

This invention resides substantially in the combination, construction,arrangement and relative location of parts, all as will be described ingreater detail in the following specification.

20 In the accompanying drawings,

Figure 1 is a front elevational view of the structure of this invention;

Figure 2 is a side elevational view thereof withsome parts broken away;

25 Figure 3 is a top plan view thereof;

Figure 4 is an inside elevational view of the gear box and partsassociated therewith showing the frame adjacent the chain pinion incrosssection;

30 Figure 5 is an elevational view looking into the gear box with itscover removed, with some parts broken away;

Figure 6 is a cross-sectional view taken on the line 6-45 of Figure 2;and

35 Figure 7 is a view looking into the brake hous- *-ing on the plane'l'| of Figure 1.

The full nature of the novelty and scope thereof as incorporated in thisinvention will be more quickly understood by first describing thestruc-- 40 tural details thereof. The main frame of the de-. viceconsists of a ring-like casting I within which a standard fractionalhorsepower electric motor 2 is secured in the manner clearlyillustrated. The housing casting l is provided with an inte- 45 graljournal member 4 at the bottom thereof provided with an integral bracketmember 5 to which The gear housing is provided with aion 8 which mesheswith the driven gear '9, the projecting inner end of the motor shaftbeing journaled in a bearing I keyed in the gear housshaft I3. Shaft l3extends through the back of the gear housing and into the journalhousing 4.

As is clear from Figures 1 and 4, the journal 10 housing is dividedlongitudinally into two parts to provide an opening into which the chainpinion fits. The pinion is mounted on a short shaft I 3a. The pinion '5lies in a bearing block I4 which is U-shaped in form so that the pinionl5 lies between the legs thereof, as is clear from Figure 4. The blockl4 closes the lower half of, the space in the bearing member 4 and issecured to and held in place by means of a bar I5 which is attached tothe casting, as is clear from Fig- 2 ures 1 and 4, by screws or bolts.By this arrangement the chain is guided in its movement over the pinionl5.

The hoist chain is shown at It, the'upper free end of which is attachedto the casting l by means of a hook I! mounted on the casting. As isclear from Figure 4, the chain hangsin a loop between the pinion 15 andthe hook ll. The other end of the chain is provided with the loadinghook l8 which is attached thereto by means of a U-shaped yoke l9 andrivets, as is clear from Figure 4. Secured by these same rivets is anL-shaped bracket 20 which performs a function which will be describedlater. The suspension book, by means of which the device is supported.from overhead, is shown at 2| secured in any suitable manner to thecasting I. It is noted that the hook 2| is mounted directly over thepinion l5 and the weight of the various parts on either side of the axiswhich includes them is so distributed that the device is nicelybalanced. This is of practical advantage since the loads on the chainare directly transmitted through the casting I to the overhead supportwithout danger of I causing the device to tip or swing.

As shown in Figures 6 and 7 the shaft l0 extends into the brake housing22 and has secured on the end of it a disc-like member 24 which in turnloosely supports the inner brake disc 25.

The disc 25 is held properly positioned and is 30, positioned to engagethe ring 24. When the' member 3| is revolved in either direction thedisc 30 is caused to have an axial movement either towards or away fromthe friction ring 25. Secured to the outer face of the member 35 bymeans of a screw 33 is the lever 32. At one end of the lever 311s ahandle 34 secured thereto by a suspending cord while there is mounted onthe other end of the lever a weight 35. The threads of the member 3| arepitchedin such a direction that when lever 32 is free the weight 35tends to move the member 3| and the disc 30 inwardly to cause the disc30 to engage the ring 25.

As will be apparent by tracing the motions through, a weight suspendedon the hook i6 will tend to rotate the disc in a direction so as to tendto cause the member 3| to move inwardly. Thus all of the forcesinvolved. including the weight 35, are in a direction to tend to causethe brake to grip and hold the chain against movement. The various leverarms involved are so proportioned in relation to the strength of thesprings 29, of which there are several distributed circumferentiallyaround the disc 24,

' that all loads on the hook I8 up to the capacity,

of the device are insufiicient to cause any movement of the mechanismunaided by the motor. However, when the motor is energized to move thehook l8 downwardly the resistance of the 40 brake mechanism is overcomeso that the hook I desired to lower the hook bearing a load without thering 26 to release the brake.

employing the motor this is done by releasing the brake, which isaccomplished by pulling down on the handle 34. This rotates the member3| in a direction so that the disc 30 moves away from By making the arm32 of the proper length this control may be very sensitive and theloaded hook may be caused to descend very slowly or in small incrementsso as to be always under control. As soon as the handle 3| is releasedthe .weight 35 plus the tendency of the rotation of the disc 24 underthe load of the hook are such as to cause the brake to firmly grip andstop all movement.

Mounted on top of the gear casing 3 is a switch 35, the details ofconstruction of which are unnecessary to a full understanding of theinvention except to note generally that when the switch is turned fromits neutral position in one direction the motor, which is reversible, isenergized for rotation in one direction, and when the switch is movedfrom neutral to its other position the motor is energized in the reversedirection. In this connection, depending upon the nature and field ofuse of the device, the switch may be of a type which requires continuousconscious effort to maintain it in either actuated position or may be ofa type which remains in actuated position until returned to neutralposition. The actuating shaft for the switch is shown at 38 and hassecured thereto a This ring is attached by rivets. as is.

pulley 35 and a pinion 4|. Mounted on the pulley and preferably attachedthereto are a pair of depending cords 4| which pass through guideeyelets 42 mounted on the gear housing and terminate in handle grips 41and 44. At 45 and 45, respectively, are indicators which indicate, forexample in the case of indicator 45, that when handle 43 is pulleddownwardly the hook will move down and when handle 44 is pulleddownwardly the indicator 45 indicates that the hook will move up.

At 41 is a rack member meshing with the pinion and secured to a verticalslidable bar mounted in a suitable guide member 45 on the rear face ofthe gear housing 3. The lower end of the bar 48 isprovided with a pin5|! which extends through the slot in the end of a lever 5| pivotallymounted intermediate its ends on the rear face of the gear housing, asis clear from Figure 4. The other end of the lever 5| is provided with apin 52 which is positioned to be in the path of travel of the arm 20 onthe hook yoke. Pin 50 is positioned so as to be over the loop in thechain I5 between the chain pinion l5 and the hook I1.

To operate the device, handle 43 is pulled downwardly which rotates thepulley 39 and closes the switch to set up connections-so that the motor2 will rotate pinion 15 through the gear train in a direction to movethe chain downwardly. At the same time pinion 40 moves the rack 41, bar48, and right hand end of lever 5|, Figure 4, downwardly so that thelever is in the dotted position shown. Thus the hook is lowered whetherloaded or not, and if by oversight switch 35 is not shut off in time theshortening loop in the chain I6 will ultimately engage the pin 50 tomove bar 48 and rack 47 upwardly, which will move the switch back tonormal position and deenergize the motor- Thus the mechanism is stoppedbefore the chain is drawn tight, eliminating'any tendency to break thechain or the hook ll. Lever 5| is at the same time moved to neutral orfull line position. The nature of this automatic stopping mechanism issuch that even if the operator should hold on to the handle 43, which hewould do particularly in the case of a switch that had to be held inoperated position, the switch will be returned to neutral position. Toraise the hook, handle 44 is pulled downwardly which rotates the switchin the reverse direction and moves lever 5| to the other dotted position(Figure 4) through the rack 41 and the bar 48. In this case the pin 52is downward and in the event that the operator overlooks shutting offthe device in time the arm 20 will engage the pin 52 moving lever 5|back to full line position and at the same time returning the switch 'toneutral position to deenergize the motor.

The device of this invention is amazingly small, compact and rugged. Thedevice, as illustrated, has an over-all width of not much more than afoot and weighs in its present form but fifty pounds. Nevertheless, thedevice is capable. of lifting a load of five hundred pounds or in theratio of ten to one with respect to its weight. It is anticipated thatupon further design the weight may be reduced to about thirtypoundswhich will render the device easily portable and of great utility.Because of the simplicity of the structure involved the cost ofmanufacture is relatively low and the device is already demonstratingcommercially these remarkable characteristics.

It will be apparent to those skilled in the art as that the details ofconstruction employed for illustrating the principles of the inventionmay be varied Without departure from the true nature and scope of theinvention. It is desired, therefore, not to be limited to the disclosurebut rather to the appended claim.

What I seek to secure by Letters Patent is:

A portable electric hoist having, in combination, a supporting structurecomprising a. ring adapted to be supported with its axis horizontallydisposed, an electric motor having a drive shaft, a. cylindrical motorcasing carried by and projecting from one end of said ring, and an endshield on said casing providing a bearing for said shaft and closing theprojecting end of the casing, the other end of said motor shaftprojecting from said ring, said supportingstructure further com-prisinga journal member formed integrally with said ring and positioned at thebottom of said ring, a gear case rigid with said journal member at theend opposite said motor and providing a bearing for said projecting endof the motor shaft, and a hoisting mechanism comprising a driven shaftjournaled in said journal member in spaced parallel relation to andbelow the motor shaft, and speed reduction gearing mounted in saidcasing and connecting said shafts.

PRESTON WHITCOMB.

